Exhaust gas recirculation EGR systems in internal combustion engines are controlled or metered by an EGR valve. The EGR valve meters the amount of EGR that will be introduced into the engine. The inlet flows and outlet flow are controlled by an EGR valve.
As shown in FIG. 1, cartridge-style EGR valves 10 typically include an actuator 12 and a valve stem 14 having two valve heads 16, 18. As shown in FIG. 1, the valve device 10 is placed in a valve housing 20 in the exhaust manifold or EGR valve body of an engine, which must have valve seats 22 machined or inserted therein. The valve heads 16, 18 are shown in the open position. This arrangement allows for three chamber EGR metering; the valve can control two inlet passages 24, 26 which join to form a single outlet passage 28. This does not permit full use of the pressure pulses in the exhaust flow by the turbocharger system or the EGR system.
The invention provides a solution in a drop-in cartridge style, four-chamber EGR valve.
According to the invention, the cartridge valve includes a valve actuator, a valve stem extending from the valve actuator and having two valve heads mutually spaced on the stem, and a cage or frame having a plurality of axially extending bars connected by first and second ring assemblies, the ring assemblies being circumferential members.
According to the invention, the cage is divided along a longitudinal axis into two mating parts. The division of the cage longitudinally provides a “clam shell” configuration that allows for simple assembly of the valve device. The mating parts of the cage allow the valve stem to be installed in the valve actuator and the cage assembled around the valve stem and valve heads in a simple manner.
According to the invention, the first and second ring assemblies each have formed thereon a valve seat for one of the valve heads. Thus, the requirement of machining or forming the valve seats in the valve housing is eliminated.
According to the invention, the cage may include a third ring assembly connecting the axially extending bars and disposed between the two ring assemblies with a sealing disk mounted to the third ring assembly to divide the cage axially. The sealing disk may be formed in two parts, one part being attached to each mating part of the cage, wherein, upon mating of the mating parts, the two parts of the sealing plate are joined as an integral disk.
According to the invention, the ring assemblies may include seats for accepting an o-ring, the seats being formed on a radially outer surface of each ring assembly. The assembly may further comprise an o-ring mounted in each of the seats. The o-rings are configured to contact the inner walls of valve housing formed in the exhaust manifold or EGR valve body and thus provide seals in the valve housing to seal the four chambers from one another.
Additional ring assemblies or circumferential members may be provided for structural support or for seating and sealing the frame in the valve housing.
According to the invention, the cage may include four ring assemblies, an end ring assembly providing structural rigidity to the cage.